Electric switch contact



June 8,1948 J,w,McLA.N 2,443,047

ELECTRIC SWITCH CONTACT Filed May 51, 1946 Inventor-r Joseph W. McClain,

b win 77w.

His Attorne g.

Patented June 8, 1948 ELECTRIC SWITCH CONTACT .Joseph W. McClain,Logansport, Ind., assignor to General Electric Company, a corporation ofNew York Application May 31, 1946, Serial No. 673,277

My invention relates to electric switch contacts,

and has for its object the provision of means for renderingsubstantially shock-proof the heavy contacts of large electromagneticcontactors.

The invention will be more fully understood and its objects andadvantages further appreciated by referring to the following detailedspecification taken in conjunction with the accompanying drawing, inwhich Fig. 1 is a side elevation of an electromagnetic contactorembodying my invention, Fig. 2 is an end view of the contactor shown inFig. 1, and Fig. 3 is an exploded perspective view showing in detail themounting of the movable contacts shown in Figs. 1 and 3.

Referring now .to the drawings, and particularly to Figs. 1 and 2, Ihave shown an electromagnetic contactor mounted upon a base I andcomprising a rectangular shaft 2 rotatably mounted at its ends inbearings 3. The shaft 2 carries a plurality of movable contacts 4 and amagnetizable armature 5. The contacts 5 are arranged to engage anddisengage cooperating fixed contacts 6 mounted upon the base I. Theshaft 2 also-carries a weight 1 arranged to bias the shaft 2 to a normalposition of contact disengagement. A pair of electromagnets 8 aremounted upon the base I for cooperation with the armature 5. When theelectromagnets are energized they attract the armature 5, thereby tomove the shaft 2 and to contact engaging position.

At Fig. 3, I have shown in detail the mounting of the movable contactblocks 4. Each contact block is loosely mounted for pivotal movement ina generally V-shaped supporting saddle 9 fixed to the rotatable shaft-2.The contact block 4 is biased against the front side of the saddle 9 bya wipe spring I0. The wipe spring I is a helical compression springpositioned between the back of the contact block 4 and a spring seatformed-by an up-turned ear II on the rear side of the supporting saddle9.

The contact block 4 is provided at its lower end with a V-shapedtransverse notch l2, and is pivotally mounted upon a knife-edge bearingl3 protruding from the front side of the saddle 9 and cooperating withthe V-shaped notch l2. The block 4 is held on its knife-edge support bythe wipe spring In.

In order to prevent lateral displacement of the contact block 6 withinthe saddle 9, I provide a r pair of guide plates I 4, 15 attached to thefront side of the supporting saddle! and embracing the sides of thecontact block I. In the embodiment of the invention shown in thedrawing, the guide plates ll, I are formed by the sides of a U-shaped 2Claims. (Cl. 200166) 2 member IS, the lower end of which is turned up toform the knife-edge bearing l3. The U-shaped member is welded orotherwise fixedly attached to the front side of the supporting saddle 9.

I have found that with the construction hereinbefore described, thecontact blocks 4 are subject to longitudinal displacement within theguide plates l4 and IS in the event of severe impact applied to thecontactor. In order to prevent such longitudinal displacement whilepermitting the slight pivotal movement of the contact blocks necessaryfor proper wiping action, I provide between each contact block and atleast one of the guide plates I, I5 a lost motion interlockingconnection. Such a connection may be formed by providing at one'sideofeach contact block 4 a pin arranged in interfltting relation with a slotin one of the guide plates l4, l5. Specifically in the illustrated formof the invention, I have shown a pin formed upon the side of eachcontact block 4 by threading into the contact block a fillister headbolt ll. protrudes into an elongated slot iii in the guide plate l5. Itwill be evident that the pin and slot connection l1, l8 between thecontact block 4 and the guide plate l5 prevents longitudinaldisplacement of the contact block while permitting a limited pivotalmovement of the block on its knife-edge support l3.

While I have described only a preferred embodiment of my invention byway of illustration, many modifications will occur to those skilled inthe art and I therefore wish to have it understood that I intend in theappended claims to cover all such modifications which fall within'thetrue spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the Unitedstates is:

1. An electric contactor comprising a movable contact support providinga knife-edge bearing, a contact block pivotally mounted on saidknifeedge bearing for movement relative to said support, a pair of guideplates embracing the sides of said contact block to prevent lateraldisplacement of said block in said support, and a lost motion pin andslot connection between said contact block and at least one of saidguide plates, thereby to prevent longitudinal displacement of said blockwhile permitting limited pivotal movement thereof. v

2. An electric contactor comprising a rotatable contact supportproviding a knife-edge bearing, a movable contact block loosely mountedupon said knife-edge bearing for pivotal movement relative to saidsupport, spring means retaining The head of the bolt l'l 3 said contactblock in position upon said knife-- edge bearing while permittinglimited pivotal movement 01 said block, a pair of guide plates embracingthe sides 01 said contact block to prevent lateral displacement of saidblock in said support, and a lost motion pin and slot connection betweensaid contact block and at least one of said guide plates for preventinglongitudinal displacement of said block while permitting limitedpivotal'movement thereof in said support.

JOSEPH W. McCLAIN.

'4 REFERENCES CITED The following references are 01 record in the fileor this patent:

v UNITED sums PATENTS Number Name Date 706,527 Carichoi! Aug. 12, 19022.1mm schaelchlin Dec. 26, 1939 2,397,113 Igiehart Mar. 26, 1946

